Various semiconductor components include contact bumps that provide connection points between the integrated circuits included in the component and the outside world. For example, bumped semiconductor wafers can include patterns of contact bumps. Singulated unpackaged dice, such as known good die (KGD), can also include contact bumps which permit the dice to be flip chip mounted in multi chip modules and other electronic systems. Other semiconductor components, such as packaged dice and chip scale packages, can also include contact bumps.
Typically, lead tin alloys (e.g., 95/5 lead tin alloy) and a ball limiting metallurgy (BLM) process are used to form the contact bumps. With this process the contact bumps are dome shaped, and have an average diameter of from 5 mils to 30 mils. The sides of the bumps typically bow or curve outwardly from flat top surfaces. The flat top surfaces of the bumps form the actual areas of contact with contacts on a mating electrical component (e.g., circuit board). In addition, the contact bumps can be formed on the component in a dense array such as a ball grid array (BGA). Micro ball grid arrays are formed in the smaller range, while standard ball grid arrays are formed in the larger size range.
With bumped semiconductor components, it is sometimes necessary to make non-bonded, or temporary, electrical connections with the contact bumps. For example, contact bumps can be used for probe testing of semiconductor wafers, or for burn-in testing bumped dice and packages. For testing unpackaged dice and chip scale packages, temporary packages can be used to house the dice or packages during the testing procedure.
In the past, following testing of semiconductor components having contact bumps, it has been necessary to reflow the bumps, which are typically damaged by the test procedure. This is an additional process step which adds to the expense and complexity of the testing process. Furthermore, the reflow process requires heating the tested components which can adversely affect the integrated circuitry contained in the component.
Another problem with making temporary electrical connection with contact bumps is that the sizes of the contact bumps can vary between different components, or within the same component. For example, typical contact bumps for a particular type of component can have diameters between 4.5 mils to 5.5 mils. In addition, the x-y location, and the planarity (i.e., z-direction location), of the contact bumps can also vary. These dimensional variations can cause misalignment making reliable temporary electrical connections difficult to form with the contact bumps.
Because of the increasing use of contact bumps in semiconductor manufacture, improved interconnects are needed for making temporary electrical connections to the contact bumps.